using System;
using System.Text;

using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Asn1.X509
{
	/**
	 * The DistributionPoint object.
	 * <pre>
	 * DistributionPoint ::= Sequence {
	 *      distributionPoint [0] DistributionPointName OPTIONAL,
	 *      reasons           [1] ReasonFlags OPTIONAL,
	 *      cRLIssuer         [2] GeneralNames OPTIONAL
	 * }
	 * </pre>
	 */
	public class DistributionPoint
		: Asn1Encodable
	{
		internal readonly DistributionPointName	distributionPoint;
		internal readonly ReasonFlags			reasons;
		internal readonly GeneralNames			cRLIssuer;

		public static DistributionPoint GetInstance(
			Asn1TaggedObject	obj,
			bool				explicitly)
		{
			return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
		}

		public static DistributionPoint GetInstance(
			object obj)
		{
			if(obj == null || obj is DistributionPoint)
			{
				return (DistributionPoint) obj;
			}

			if(obj is Asn1Sequence)
			{
				return new DistributionPoint((Asn1Sequence) obj);
			}

			throw new ArgumentException("Invalid DistributionPoint: " + obj.GetType().Name);
		}

		private DistributionPoint(
			Asn1Sequence seq)
		{
			for (int i = 0; i != seq.Count; i++)
			{
				Asn1TaggedObject t = Asn1TaggedObject.GetInstance(seq[i]);

				switch (t.TagNo)
				{
				case 0:
					distributionPoint = DistributionPointName.GetInstance(t, true);
					break;
				case 1:
					reasons = new ReasonFlags(DerBitString.GetInstance(t, false));
					break;
				case 2:
					cRLIssuer = GeneralNames.GetInstance(t, false);
					break;
				}
			}
		}

		public DistributionPoint(
			DistributionPointName	distributionPointName,
			ReasonFlags				reasons,
			GeneralNames			crlIssuer)
		{
			this.distributionPoint = distributionPointName;
			this.reasons = reasons;
			this.cRLIssuer = crlIssuer;
		}

		public DistributionPointName DistributionPointName
		{
			get { return distributionPoint; }
		}

		public ReasonFlags Reasons
		{
			get { return reasons; }
		}

		public GeneralNames CrlIssuer
		{
			get { return cRLIssuer; }
		}

		public override Asn1Object ToAsn1Object()
		{
			Asn1EncodableVector v = new Asn1EncodableVector();

			if (distributionPoint != null)
			{
				//
				// as this is a CHOICE it must be explicitly tagged
				//
				v.Add(new DerTaggedObject(0, distributionPoint));
			}

			if (reasons != null)
			{
				v.Add(new DerTaggedObject(false, 1, reasons));
			}

			if (cRLIssuer != null)
			{
				v.Add(new DerTaggedObject(false, 2, cRLIssuer));
			}

			return new DerSequence(v);
		}

		public override string ToString()
		{
			string sep = Platform.NewLine;
			StringBuilder buf = new StringBuilder();
			buf.Append("DistributionPoint: [");
			buf.Append(sep);
			if (distributionPoint != null)
			{
				appendObject(buf, sep, "distributionPoint", distributionPoint.ToString());
			}
			if (reasons != null)
			{
				appendObject(buf, sep, "reasons", reasons.ToString());
			}
			if (cRLIssuer != null)
			{
				appendObject(buf, sep, "cRLIssuer", cRLIssuer.ToString());
			}
			buf.Append("]");
			buf.Append(sep);
			return buf.ToString();
		}

		private void appendObject(
			StringBuilder	buf,
			string			sep,
			string			name,
			string			val)
		{
			string indent = "    ";

			buf.Append(indent);
			buf.Append(name);
			buf.Append(":");
			buf.Append(sep);
			buf.Append(indent);
			buf.Append(indent);
			buf.Append(val);
			buf.Append(sep);
		}
	}
}
